Degradation of insulating papers

Main regulatory references IEC TR 62874:2015, “Guidance on the interpretation of carbon dioxide and 2-furfuraldehyde as markers of paper thermal degradation in insulating mineral oil” CIGRE Technical Brochure 227, 2003 “Life Management Techniques for Power Transformer” CIGRE Brochure 323, 2007 “Ageing of cellulose in mineral-oil insulated transformers” CIGRE Brochure 343,2008 “Recommendations for condition monitoring and condition assessment facilities for transformers”Read more

Electrical insulation In electrical transformers, insulation is mainly ensured by the sum of solid materials, such as kraft paper, and insulating fluids, mainly mineral oils.This important innovation was invented and claimed by well-known scientist Nikola Tesla from patent No. 655,838 "Method of Insulating Electric Conductors" of 14 August 1900, "my invention of any kind of fluid capable of meeting theRead more

There is no therapy able to "rectify" the "degradation of insulating papers" criticality. Degradation is an irreversible process that can only be managed through appropriate prevention and/or mitigation actions. Paper replacement is not a viable option because the cost would be close to the cost of fully replacing the transformer. When the paper DP reaches a value of 200, whichRead more

Paper, kraft paper, insulating paper, cardboard/precompressed cardboardpaper  (from Electropedia IEC) cellulosic paper of certain types, frequently characterized by their relatively high rigidity Note – In general the term paper is used for cellulosic papers if not otherwise specified. [source] Kraft paper (from Wikipedia) Electrical insulation paper (from Wikipedia) (paper) board - cardboard, precompressed cardboard (from IEC Electropedia) generic term applied toRead more

For diagnosis of the "Degradation of insulating papers" criticality, Sea Marconi uses its own diagnostic metrics, namely: visual signs on the transformer (and those from any internal inspection) are interpreted; through analysis of the papers (if available as a result of internal inspection) and oil, the symptoms and their values are identified. In particular, for some indicators such as 2FALRead more

Sampling of oil, and even more so of papers, must be carried out by qualified operators according to protocols and procedures laboratory analyses must be carried out using methods set by reference standards, as guaranteed by accredited laboratories action to prevent the "Degradation of insulating papers" criticality, in this case the treatments of oil depolarisation and internal inspections of theRead more

"Degradation of insulating papers" is an irreversible process that can, however, be prevented or mitigated through specific actions. By arranging appropriate operational practices (e.g. analytical oil control, oil and paper treatment, load profile management, cooling of the machine), it is possible to reduce the probability of failure and prolong the operating life of the transformer under examination.If the transformer isRead more

Signs (visual inspection) The direct visual signs of this criticality are only highlighted by internal transformer inspection. In the case of failure (or end of life) of twin machines, for example, it is good practice to perform a paper diagnostics (through sampling, analysis and interpretation) in order to determine an experimental reference for the transformer concerned. In the presence ofRead more

The "Degradation of insulating papers" criticality is caused mainly by normal ageing mechanisms and by particular conditions of thermal, electrical and mechanical stress on insulating papers. Causes in relation to life cycle phases Causes of the "Degradation of insulating papers" criticality When it may occur (life cycle phases) Lack of purchase requirements for insulating papers Requirements and purchase Deficiency inRead more

Symptoms (analysis) The specific symptom of the "Degradation of insulating papers" criticality is related to the presence of non-conforming oil values for the following diagnostic indicators: Water in oil (IEC 60814) Oxygen CO2 – carbon dioxide CO – carbon monoxide 2FAL - 2furaldehyde and other furan compounds Methanol Ethanol Particles (IEC 60970) Gases symptomatic of hot spots (methane, ethane, ethylene)Read more